| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [verb] [prep] a period | 506 |
|
| 2 | occur [prep] a [noun] | 343 |
|
| 3 | occur [prep] a [noun sg] | 335 |
|
| 4 | occur [prep] [art] period | 21 |
|
| 5 | occur [prep] [art] period | 21 |
|
| 6 | occur [prep] a period | 9 |
|
| 7 | occur [prep] a period | 9 |
|
| 8 | occur [prep] a period | 9 |
|
